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Geology 


THE   ELEMENTS   OF   BLOWPIPE 
ANALYSIS 


THE 

ELEMENTS    OF    BLOWPIPE 
ANALYSIS 


BY 


FREDERICK  HUTTON  GETMAN,  F.C.S. 

INSTRUCTOR  IN  CHEMISTRY  IN  THE  STAMFORD 
HIGH  SCHOOL 


godt 
THE    MACMILLAN   COMPANY 

LONDON  :  MACMILLAN  &  CO.,  LTD. 
1899 

All  rights  reserved 


BY  THE  MACMILLAN  COMPANY. 


Nortoonfi 
J.  8.  Gushing  &  Co.  -  Berwick  Sc  Smith 
Norwood  Mass.  U.S.A. 


PREFACE 

THESE  few  pages  are  intended  to  serve 
a  twofold  purpose,  —  to  give  the  student 
a  general  outline  of  Blowpipe  Analysis, 
and  to  introduce  him  to  the  methods  of 
Determinative  Mineralogy. 

Every  effort  has  been  made  to  simplify 
details  so  that  the  book  may  be  used  in 
both  High  Schools  and  Colleges. 

Tables  for  "  systematic  "  examination  have 
been  intentionally  omitted,  for  in  the  au- 
thor's estimation  these  tend  to  dull  the 
student's  power  of  observation,  and  to  make 
him  place  little  value  upon  minute  details. 

The  alphabetic  arrangement  has  been 
followed  for  the  sake  of  convenience  when 
referring  to  the  book. 

819488 


Vi  PREFACE 

The  last  chapter  is  not  intended  to  serve 
as  a  key  to  determining  the  minerals  therein 
described,  but  rather  it  is  added  to  give 
the  student  exercise  in  Blowpipe  Analysis, 
and  at  the  same  time  to  point  out  the 
methods  of  Determinative  Mineralogy. 

Finally,  the  author  would  acknowledge  his 
indebtedness  to  the  following  works  :  "  Man- 
ual of  Qualitative  Analysis,"  Fresenius; 
"Qualitative  Chemical  Analysis,"  Venable; 
Roscoe  and  Schorlemmer's  "  Treatise  on 
Chemistry";  Foye's  "  Hand- Book  of  Min- 
eralogy"; Dana's  "Mineralogy";  Kobell's 
"Tafeln  zur  Bestimmung  der  Mineralien"; 

etc. 

FREDERICK  HUTTON  GETMAN. 

STAMFORD,  CONN., 
Feb.  22,  1899. 


TABLE   OF  CONTENTS 


CHAPTER  I 

PAGE 

Apparatus  and  Reagents 1-7 


CHAPTER  II 

General  Outline  of  Blowpipe  Analysis 8 

Definitions 9 

Examination  on  Charcoal  Alone 10 

Examination  on  Charcoal  with  Sodium  Carbonate  .        .  13 

Examination  in  Tube  with  Sodium  Carbonate  and  Charcoal    .  15 

Examination  on  Platinum  Wire 16 

Examination  in  Borax  Bead 17 

Examination  with  Cobalt  Nitrate 20 

CHAPTER  III 

General  Reactions  for  the  Detection  of  the  Metallic  Ele- 
ments in  Simple  Compounds 22 

Aluminum 23 

Antimony 24 

Arsenic 25 

Bismuth -     •  •     .    '     ,  25 

Cadmium 26 

Chromium 26 

Cobalt     ..........  27 

vii 


viii  CONTENTS 

PAGE 

Copper 28 

Iron 28 

Lead 29 

Manganese 30 

Mercury 30 

Nickel 31 

Silver 32 

Tin 32 

Zinc 33 

The  Alkali  Metals 34 

Ammonium 34 

Potassium 35 

Sodium 35 

Lithium 36 

The  Alkaline  Earths 36 

Barium 36 

Calcium 37 

Strontium 37 


The  Acid  Elements 


37 


Borates 37 

Bromides 38 

Chlorides 38 

Fluorides 38 

Iodides 39 

Nitrates 39 

Phosphates 40 

Silicates .         .        .         .40 

Sulphides .         .41 


CONTENTS  IX 
CHAPTER  IV 

PAGE 

Behavior  of  Some  of  the  Principal  Ores  before  the  Blowpipe  43 

Ores  of  Antimony •••'..        .        .  46 

Ores  of  Arsenic        .         .        .        .  "*    .        .        .        -47 

Ores  of  Bismuth       .        »        ,        .        .        .     .  .        .  48 

Ores  of  Chromium 49 

Ores  of  Cobalt 50 

Ores  of  Copper ,        ,  52 

Ores  of  Iron 57 

Ores  of  Lead 60 

Ores  of  Manganese 63 

Ores  of  Mercury 64 

Ores  of  Nickel 65 

Ores  of  Silver 66 

Ores  of  Tin i        .        .  69 

Ores  of  Zinc 70 

COMPARATIVE  TABLES 

I.    Colors  of  Coatings  on  Charcoal 73 

II.     Flame  Colorations          ,    •'  9 73 

III.  Colors  of  Borax  Beads  in  oxidizing  Flame      ...  74 

IV.  Colors  of  Borax  Beads  in  reducing  Flame      ...  75 
V.     Colors  of  Microcosmic  Salt  Beads  in  oxidizing  Flame    .  76 

VI.     Colors  of  Microcosmic  Salt  Beads  in  reducing  Flame     .  77 


FORCEPS 
Fig.  5 


AGATE  MORTAR  &  PESTLE 
Fig.  4 


HAMMER 
Fig,  6, 


3 -CORNERED  FIJ_ES 
Fig,  7 


BLOWPIPE   ANALYSIS 

CHAPTER   I 

THE  blowpipe  was  first  applied  to  mineral 
analysis  in  1733  by  Anton  Swab,  and  its 
applications  have  since  been  improved  and 
extended  by  various  chemists,  among  whom 
may  be  mentioned  Bergmann,  Cronstedt, 
Gahn,  Berzelius,  and  Plattner. 

Blowpipe.  —  The  common  blowpipe  of  the 
jeweller  is  not  particularly  well  suited  to 
the  operations  of  blowpipe  analysis,  since 
the  flame  has  often  to  be  kept  playing 
upon  the  assay  for  some  time,  and  the 
condensed  moisture  of  the  breath  would 
seriously  interfere  with  the  passage  of  the 


«  BLOWPIPE  ANALYSIS 

air  through  the  jet.  One  of  the  best  and 
least  expensive  forms  of  blowpipe  is  shown 
in  Fig.  i.  This  consists,  as  is  seen  from 
the  illustration,  of  a  conical-shaped  tube  of 
tin  closed  at  the  wide  end  and  formed  into 
a  mouthpiece  at  the  small  end;  soldered 
into  the  tube  at  the  large  end,  and  at 
right  angles  to  its  axis,  is  a  small  brass 
tube  which  terminates  in  a  conical  tip 
pierced  with  a  very  fine  hole.  With  this 
pipe  it  is  possible  to  perform  all  of  the 
operations  of  mineral  analysis. 

Some  little  practice  is  necessary  to  keep 
the  flame  steady  and  to  take  the  breath  at 
the  same  time. 

No  rule  can  well  be  given  to  the  begin- 
ner, but  his  experience  becomes  his  best 
guide. 

Bunsen  Flame.  —  Any  kind  of  flame  can 
be  used  for  the  blowpipe,  provided  it  be 


BUNSEN  FLAME  3 

not  too  small ;  but  since  almost  every  labo- 
ratory to-day  is  furnished  with  gas  and  the 
Bunsen  burner  (Fig.  2),  it  will  only  be 
necessary  to  describe  the  use  of  the  flame 
from  this  source.  Upon  examining  the 
Bunsen  flame  with  care,  it  will  be  seen  that 
the  flame  consists  of  three  distinct  parts. 

A  dark  inner  cone  which  consists  of  gas 
not  yet  raised  to  the  ignition  point.  Be- 
yond this  there  is  a  luminous  cone,  where 
combustion  is  incomplete  owing  to  lack  of 
oxygen,  and  outside  of  this  we  find  the 
non-luminous  cone  where  the  gas  is  com- 
pletely burned. 

This  outer  envelope  is  the  hottest  por- 
tion of  the  flame,  and  is  known  as  the 
"  oxidizing  "  flame  because  there  is  an  excess 
of  oxygen  which  is  imparted  to  substances 
placed  therein. 

The  luminous  cone  is  known  as  the 
"reducing"  flame,  for  in  it  metallic  oxides 


4  BLOWPIPE  ANALYSIS 

are  reduced,  the  oxygen  being  taken  up 
by  the  small  incandescent  particles  of  car- 
bon. 

If  the  air-holes  at  the  base  of  the  Bun- 
sen  burner  be  opened,  the  two  inner  cones 
become  elongated,  and  the  flame  appears 
almost  colorless. 

The  blowpipe  enables  us  to  get  an  oxidiz- 
ing and  a  reducing  flame  of  better  form 
and  greater  power.  To  do  this  we  cut  off 
the  air  supply  at  the  base  of  the  burner 
and  turn  off  the  gas  until  the  flame  is 
about  i  cm.  high;  then  upon  introducing 
the  blowpipe,  and  blowing  a  strong  con- 
tinuous jet  of  air  across  the  Bunsen  flame, 
we  produce  an  oxidizing  flame  about  4-5 
cm.  in  length.  If  the  tip  of  the  blowpipe 
be  held  outside  of  the  Bunsen  flame,  and 
the  pressure  of  the  stream  of  air  be  dimin- 
ished, we  obtain  a  reducing  flame. 


BUNSEN  FLAME  5 

Supports.  —  For  supports,  charcoal,  plati- 
num, and  glass  are  chiefly  used.  The 
charcoal  should  be  made  from  some  light 
wood,  such  as  alder.  It  should  be  well 
burnt,  and  should  not  scintillate  or  smoke. 

The  platinum  supports  are  generally  in 
the  form  of  wire  and  foil.  Platinum-tipped 
forceps  are  frequently  employed  in  blow- 
pipe analysis. 

Glass  is  used  in  the  form  of  tubing. 

Hard  glass  tubing,  3  mm.  bore,  is  drawn 
off  into  ignition  tubes  7-8  cm.  in  length. 
Several  dozen  of  these  tubes  should  be 
made  before  commencing  the  tests  of  the 
next  chapter. 

Apparatus.  —  A  small  agate  mortar,  4-5 
cm.  in  diameter,  should  be  provided  in 
which  to  grind  the  samples  to  be  exam- 
ined. 

The  pestle,  which  should  also  be  of  agate, 


6  BLOWPIPE  ANALYSIS 

must  be  adapted  to  the  mortar  in  shape 
and  size. 

Two  pairs  of  forceps  will  also  be  needed. 

One  pair  should  be  of  steel,  and  the  other 
pair  of  brass,  with  fine  points. 

Of  other  apparatus,  the  most  necessary 
is:  — 

A  small  hammer  and  anvil. 

Two  three-cornered  files. 

Small  piece  of  cobalt  glass,  about  5  x  10 
cm. 

Pocket  magnifying  lens. 

Several  small  watch  glasses  —  for  metallic 
beads,  etc. 

Chemicals. — A  list  of  the  principal  chemi- 
cals is  here  given :  — 

Sodium  carbonate,  Na2CO3. 

Borax,  Na2B4O7+  ioH2O. 

Microcosmic  salt,  (HNaNH4),  PO4  +  8  H2O. 


BUNSEN  FLAME  7 

Cobalt  nitrate,  Co(NO3)2+5  H2O. 
Potassium  cyanide,  KCN. 
Hydrochloric  acid,  (dilute),  HCl  +  nH2O. 
Litmus  paper,  red  and  blue. 
Brazil-wood  paper. 

Any  other  special  reagents  which  may  be 
needed  will  be  mentioned  as  required. 


CHAPTER  II 

GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS 

[ABBREVIATIONS :  O.  F.  for  oxidizing  flame,  R.  F.  for  reducing  flame, 
Ch.  for  charcoal,  Ct.  for  coating,  Bp.  for  blowpipe.] 

IN  order  to  examine  a  substance  before 
the  blowpipe  to  determine  the  presence 
or  absence  of  certain  elements,  it  becomes 
necessary  to  arrange  a  systematic  method. 
As  with  all  branches  of  chemical  work, 
one's  success  is  largely  dependent  upon 
neatness  of  manipulation  and  carefulness  of 
observation. 

The  following  order  of  observation  is 
essentially  that  given  by  Berzelius :  — 

1.  Examination  on  charcoal  by  itself. 

2.  Examination  on  charcoal  with  NazCO3. 

8 


GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS     9 

3.  Examination    in     ignition     tube    with 
Na2CO8  and  charcoal. 

4.  Examination  on  platinum  wire. 

5.  Examination  in  borax  bead. 

6.  Examination  with  Co(NO3)2. 

After  having  examined  a  body  in  these 
six  different  ways,  we  shall  be  able  to  say 
what  are  its  principal  constituents. 

Before  describing  the  method  of  carrying 
out  these  six  different  operations,  it  will  be 
necessary  to  give  a  few  definitions  of  terms 
which  we  shall  have  frequent  occasion  to 
employ. 

Definitions.  —  Ignition  is  the  heating  of  a 
substance  to  a  high  temperature. 

Fusion  is  the  heating  of  a  substance  to 
the  melting-point. 

Intumescence  is  the  swelling  of  the  sub- 
stance upon  heating. 


10  BLOWPIPE  ANALYSIS 

Decrepitation  is  the  crackling  of  a  sub- 
stance due  to  the  sudden  expansion  of 
combined  water  upon  heating. 

Deflagration  is  the  burning  of  a  sub- 
stance with  explosive  violence,  generally 
due  to  excess  of  oxygen. 

Incandescence  is  the  white  light  emitted 
by  a  substance  that  is  infusible  when  sub- 
jected to  a  high  temperature. 

Examination  on  Charcoal  alone.  —  The  size 
of  the  assay  should  be  about  that  of  a 
mustard  seed.  This  is  sufficiently  large  to 
show  all  of  the  reactions  clearly,  and  though 
a  larger  piece  would  exhibit  the  character- 
istic phenomena,  yet  much  more  effort  is 
required.  A  very  small,  shallow  hole  should 
be  cut  in  the  Ch.  to  receive  the  assay.  The 
Bp.  flame  should  be  directed  at  an  angle  of 
about  30°  with  the  surface  of  the  Ch.  Con- 
siderable care  must  be  taken  lest  the  hole  in 


GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS  II 

the  Ch.  is  burned  too  deep  and  the  assay 
lost  in  the  coal. 

The  force  of  the  air  from  the  jet  must 
also  be  borne  in  mind  for  a  strong  blast,  or 
sudden  puffs  may  blow  the  substance  away. 

The  following  changes  are  to  be  looked 
for:  — 

a.  Whether  the  substance  is  volatile  or 
non-volatile. 

Illustrations.  Examine  before  the  Bp.  on 
Ch.  some  arsenious  oxide,  As2O3,  also  some 
alumina,  A12O3. 

b.  Whether   the   substance   is  fusible  or 
infusible. 

Illustrations.  Examine  before  the  Bp.  on 
Ch.  some  silver  oxide,  AgO,  also  some  zinc 
oxide,  ZnO. 

c.  Whether  the  substance  is  alkaline  or 
non-alkaline  when   placed   upon    moistened 
red  litmus. 


12  BLOWPIPE  ANALYSIS 

Illustrations.  Ignite  some  calcium  car- 
bonate, CaCO3,  before  the  Bp.  on  Ch.,  and 
place  residue  on  moistened  red  litmus.  In 
like  manner,  examine  some  magnesium  car- 
bonate, MgCO3. 

d.  Color   of    coating   on    Ch.   caused   by 
combination  of   metal   and   oxygen   due  to 
heat  of  Bp.  flame. 

Illustrations.  Examine  some  oxide  of 
lead,  PbO,  before  the  Bp.  on  Ch.,  also  some 
oxide  of  cadmium,  CdO. 

e.  Decrepitation. 

Illustration.  Examine  some  sodium  chlo- 
ride, NaCl,  before  the  Bp.  on  Ch. 

f.  Deflagration. 

Illustrations.  Examine  some  potassium 
nitrate,  KNO3,  before  the  Bp.  on  Ch.,  also 
some  ammonium  nitrate,  NH4NO3. 


GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS  13 

g.    Intumescence. 

Illustration.     Examine  some  alum, 

K2A12(S04)4,  •       : 

before  the  Bp.  on  Ch. 

h.    Incandescence. 

Illustration.  Examine  some  oxide  of 
barium,  BaO,  before  the  Bp.  on  Ch. 

i.  Formation  of  a  metallic  bead  —  color 
and  malleability. 

Illustration.  Examine  some  silver  oxide, 
AgO,  before  the  Bp.  on  Ch. 

Examination  on   Charcoal  with   Na2C03.  — 

Metallic  compounds  are  often  difficult  to 
reduce  with  the  blowpipe  flame  alone,  and 
hence  no  bead  is  obtained.  In  order  to 
facilitate  reduction  and  the  obtaining  of  a 
metallic  bead,  the  substance  in  a  finely 
powdered  condition  is  mixed  with  four 


14  BLOWPIPE  ANALYSIS 

parts  of  sodium  carbonate,  Na2CO3,  and 
ignited  before  the  Bp.  on  Ch.  The  me- 
tallic compound  is  decomposed,  the  metal 
being  transformed  into  the  carbonate,  which 
in  turn,  through  the  agency  of  the  Ch.  and 
the  heat  of  the  flame,  is  reduced  to  the 
free  metal.  Sometimes  the  reduction  is 
made  easier  by  adding  to  the  substance 
about  its  own  bulk  of  potassium  cyanide, 
KCN,  which  takes  up  oxygen  from  the 
compound  and  is  converted  into  potassium 
cyanate,  KCNO. 

The  reactions  in  reducing  copper  sul- 
phate, CuSO4,  with  Na2CO3  and  with  KCN 
before  the  blowpipe,  are  here  given :  — 

CuS04  +  Na2C03  =  CuC03  +  Na2SO4 1 
2  CuCO3  +  C  =  3  CO2  +  2  Cu         J 

CuSO4  +  Na2CO3  =  CuCO8  +  Na2SO4 
CuO  +  KCN  =  Cu  +  KCNO 


GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS  15 

After  obtaining  beads,  it  is  well  to  obtain 
their  coatings,  for  oftentimes  it  is  only  in 
this  way  that  we  can  distinguish  between 
the  metals. 

Examination  in  Tube  with  Na2C03  and 
Charcoal.  —  If  the  substance  in  a  finely 
pulverized  condition  be  mixed  with  twelve 
parts,  Na2CO3,  and  six  parts  of  charcoal 
powder  and  the  mixture  be  placed  in  an 
ignition  tube  and  subjected  to  heat,  the 
acid  of  the  substance  combines  with  the 
soda  and  the  metal  is  set  free. 

If  this  metal  is  volatile,  a  sublimate  is 
formed  in  the  upper  end  of  the  tube. 

Mercury  deposits  in  minute  globules, 
which  may  be  seen  with  the  magnifying 
glass.  Arsenic  forms  a  ring,  which,  when 
examined  with  the  magnifying  glass,  is  seen 
to  be  made  up  of  minute  crystals.  Am- 
monia is  recognized  by  its  characteristic 


1 6  BLOWPIPE  ANALYSIS 

odor,  and  also  by  its  turning  a  slip  of 
moistened  red  litmus  (held  over  the  mouth 
of  the  tube)  blue. 

Examination  on  Platinum  Wire.  —  Many 
substances  possess  the  property  of  impart- 
ing to  the  colorless  flame  of  the  Bunsen 
burner  characteristic  colors. 

The  chlorides  of  these  substances  exhibit 
these  flame  reactions  best,  and  hence  before 
applying  the  flame  tests  we  dip  the  wire 
which  serves  as  a  support  into  hydrochloric 
acid  and  then  into  the  substance.  When 
the  substance  has  been  taken  up  on  the 
wire,  it  is  placed  in  the  edge  of  the  long 
colorless  flame  of  the  Bunsen  burner  near 
the  apex,  when  instantly  the  flame  becomes 
tinged  with  the  characteristic  color  of  the 
substance. 

Illustrations.  Sodium  compounds  color 
the  flame  yellow,  and  a  crystal  of  potas- 


GENERAL  OUTLINE  OF  BLOWPIPE  ANAL  YSIS  I  / 

sium  dichromate  appears  colorless  in  the 
sodium  light. 

This  sodium  reaction  is  extremely  deli- 
cate, it  being  possible  to  detect  with  ease 
a  quantity  of  a  sodium  salt  less  than 
innnhnnr  of  a  milligram  in  weight. 

Potassium  colors  the  flame  purplish-violet. 

Barium  colors  the  flame  apple-green. 

Strontium  colors  the  flame  crimson. 

Calcium  colors  the  flame  orange-red,  dis- 
tinguished from  strontium,  by  appearing 
gray  when  seen  through  blue  glass. 

Boracic  acid  colors  the  flame  green  when 
the  substance  has  been  moistened  with 
glycerine. 

Examination  in  Borax  Bead.  —  Borax, 
Na2B4O7,  and  microcosmic  salt, 

NaNH4H .  P04, 
possess  the  property  of  dissolving  many  of 


1 8  BLOWPIPE  ANALYSIS 

the   metallic  oxides  at   the    temperature  of 
the  Bunsen  flame. 

For  example,  with  oxide  of  cobalt,  the 
following  reactions  take  place  with  the  two 
fluxes : — 

CoO  +  Na2B4OT  =  Co(BO2)2  +  2  NaBO2. 

On  heating,  NaNH4H.PO4,  it  is  decom- 
posed into  the  metaphosphate  of  sodium, 
NaPO8, 

CoO  +  NaPO3  =  CoNaPO4. 

Now  in  such  cases  of  solution  the  me- 
tallic oxides  impart  a  characteristic  color 
to  the  flux. 

The  platinum  wire  is  the  best  support,  — 
it  is  heated  to  incandescence  in  the  Bunsen 
flame,  and  then  is  quickly  dipped  into  the 
borax,  when  a  small  globule  will  adhere, — 
this  is  removed  to  the  flame  again  when 
the  borax  melts  to  a  clear  glassy  bead. 
While  the  bead  is  still  melted,  touch  it  to 


GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS  1 9 

the  finely  pulverized  substance  and  replace 
in  the  flame.  In  a  few  seconds  the  small 
particles  of  the  substance  will  have  dis- 
solved, and  the  bead  will  be  seen  to  have 
assumed  the  color  characteristic  of  the  sub- 
stance. Note  the  color  when  hot  and  then 
when  cold ;  often  there  is  a  wide  difference. 
Then,  too,  the  test  should  be  made  in  both 
O.  F.  and  R.  F. 

Some  analysts  prefer  to  make  a  small 
loop  in  the  end  of  the  wire  before  taking 
up  the  borax  to  make  the  bead.  Care 
should  be  taken  to  see  that  the  bead  is 
colorless  before  bringing  it  in  contact  with 
the  substance. 

As  the  depth  of  color  produced  is  largely 
dependent  upon  the  amount  of  substance 
taken,  some  little  caution  should  be  exer- 
cised to  insure  taking  up  about  the  same 
quantity  each  time. 

Illustrations.      Make   several   beads,   and 


20  BLOWPIPE  ANALYSIS 

note  the  colors  characteristic  of  the  follow- 
ing oxides:  cobalt,  nickel,  iron,  manganese, 
chromium,  and  copper. 

The  microcosmic  salt  bead  dissolves  al- 
most every  oxide  except  silica,  SiO2,  and 
this  is  seen  to  float  about  in  the  melted 
mass.  This  is  used  as  a  test  for  silica. 

Examination  with  Co(N03)2.  —  If  after  ex- 
amination on  the  Ch.  per  se,  a  white  infusible 
residue  remains,  it  is  moistened  with  a  drop 
of  cobalt  nitrate  Co(NO3)2  and  re-ignited 
before  the  Bp.,  when  a  change  of  color  will 
be  observed.  This  change  in  color  is  owing 
to  the  fact  that  the  heat  of  the  Bp.  flame 
decomposes  the  cobalt  nitrate,  nitric  acid 
being  driven  off,  and  the  remaining  CoO 
forming  with  the  oxide  of  the  residue  a 
colored  mass. 

Illustrations.  Ignite  before  the  Bp.  on 
Ch.  the  following  oxides,  —  allow  to  cool, 


GENERAL  OUTLINE  OF  BLOWPIPE  ANALYSIS  21 

add  a  drop  of  Co(NO8)2,  re-ignite,  and  note 
color,  —  aluminum,  magnesium,  zinc,  and 
calcium. 

Care  should  be  taken  to  thoroughly  ignite 
before  adding  the  cobalt  nitrate  solution. 

With  the  six  methods  of  examination  just 
given  almost  every  simple  substance  can  be 
detected,  but  should  any  doubt  remain,  a 
few  simple  tests  in  the  "  liquid  way  "  will  be 
sufficient  to  substantiate  the  blowpipe  exam- 
ination. 


CHAPTER   III 

GENERAL  REACTIONS  FOR  THE  DETECTION   OF  THE 
METALLIC  ELEMENTS  IN  SIMPLE  COMPOUNDS 

FOR  the  sake  of  convenience,  rather  than 
for  scientific  reasons,  the  following  com- 
pounds have  been  arranged  in  alphabetic 
order.  Also  the  oxides  of  the  elements  have 
been  taken,  since  they  exhibit  the  reactions 
to  best  advantage. 

The  student  should  work  through  care- 
fully each  one  of  the  tests  and  satisfy  him- 
self as  to  the  characteristic  reactions  of  the 
various  elements,  for  only  in  this  way  can 
he  expect  to  recognize  the  substances  when 
presented  to  him  as  "  unknowns."  It  is 
advisable  to  provide  a  note-book  and  rule 
it  as  follows  :  — 

22 


GENERAL  REACTIONS 


BEHAVIOR  OF  SUBSTANCE 

Before  Bp. 
onCh. 
alone 

Before  Bp. 
on  Ch.  with 
NajCO8 

In  ignition 
tube  with 
Na2CO3and 
Ch. 

In  flame  on 
platinum 
wire 

In  flame 
with  borax 
bead 

After  first 
ignition 
with 
Co(NO3)2 

- 

Remar 
Substa 

ks 

nee     __     

i.  Aluminum,  AL03.  —  Before  the  Bp.  on 
Ch.  Infusible.  No  change. 

Before  the  Bp.  on  Ch.  with  Na2CO8. 
Forms  an  infusible  compound  with  slight 
intumescence. 

In  ignition  tube  with  Na2CO3  and  Ch. 
No  change.  Moisture  driven  off. 

In  flame  on  platinum  wire.  No  change. 
Becomes  incandescent. 

In    flame    with    borax    bead.       In    O.  F. 


24  BLOWPIPE  ANALYSIS 

dissolves   slowly,  forming  a  colorless   glass 
which  remains  so  on  cooling. 

With  Co(NO3)2.  Mass  becomes  blue  upon 
re-ignition. 

2.  Antimony,  Sb203.  —  Before  the  Bp.  on 
Ch.  In  O.  F.  volatilizes  without  change. 
In  R.  F.  is  reduced  and  volatilized.  White 
coating  of  antimonious  oxide  deposited  on 
Ch.  Blue  tinge  imparted  to  flame. 

Before  the  Bp.  on  Ch.  with  Na2CO3. 
Readily  reduced. '  White  brittle  bead.  Very 
volatile,  giving  characteristic  white  coat- 
ing. 

In  ignition  tube  with  Na2CO3  and  Ch. 
Volatilized. 

In  flame  on  platinum  wire.  Volatilized. 
Colors  flame  greenish  blue. 

With  borax  bead  on  platinum  wire.  In 
O.  F.  dissolves  to  a  colorless  glass. 

With  Co(N03)2 


GENERAL  REACTIONS  2$ 

3.  Arsenic,  As203.  —  Before  the  Bp.  on  Ch. 
Very  volatile.  Strong  garlic  odor  to  fumes. 

Before  the  Bp.  on  Ch.  with  Na^COs. 
Reduced  with  emission  of  arsenical  fumes. 

In  ignition  tube  with  Na2CO3  and  Ch. 
Volatilizes,  forming  a  mirror-like  deposit 
of  metallic  As  in  the  cooler  part  of  tube. 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire 

With  Co(N03)2_. 


4.  Bismuth,  Bi203.  —  Before  the  Bp.  on 
Ch.  Yields  a  coating  —  orange-yellow 
when  hot,  lemon-yellow  when  cold.  The 
yellow  coating  usually  has  a  white  outline. 

Before  the  Bp.  on  Ch.  with  Na2CO3. 
Easily  reduced  to  metallic  bismuth.  Yellow 
bead  brittle,  but  less  so  than  antimony. 

In  ignition  tube  with  Na2CO3  and  Ch. 


26  BLOWPIPE  ANALYSIS 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire. 
In  O.  F.  small  quantity  dissolves  to  a  clear 
yellow  glass,  which  becomes  colorless  when 
cold 

With  Co(NO3)2 _.. ._ 

5.  Cadmium,    CdO. —  Before   the    Bp.    on 
Ch.      Gives  a  coating  on  the  coal.      Red- 
dish-brown when  cold.     Very  volatile. 

Before  the  Bp.  on  Ch.  with  Na2CO3. 
Readily  reduced.  The  metal  volatilizes 
easily,  giving  the  characteristic  coating. 

In  ignition  tube  with  Na2CO3  and  Ch. 

In  flame  on  platinum  wire 

With  borax  bead.     In  O.  F.  dissolves  to  a 
clear  yellowish  bead,  colorless  when  cold. 
With  Co(N08)2 

6.  Chromium,  Cr203.  —  Before  the  Bp.  on 
Ch.     No  change. 


GENERAL  REACTIONS  2/ 

Before  the  Bp.  on  Ch.  with  Nc^COg. 
Cannot  be  reduced.  Soda  sinks  in  Ch. 
and  a  green  colored  mass  remains. 

In  ignition  tube  with  Na2CO3  and  Ch. 

In  flame  on  platinum  wire 

With  borax  bead.  Dissolves  slowly  but 
colors  intensely.  Yellow  while  hot,  green 
when  cold. 

With  microcosmic  salt  bead.  Colors  red 
when  hot,  green  when  cold. 

With  Co(NO3)2 

7.  Cobalt,  CoO.  —  Before  the  Bp.  on  Ch. 
In  O.  F.  unchanged.  In  R.  F.  is  reduced 
to  the  metal  and  is  magnetic. 

Before  the  Bp.  on  Ch.  with  Na^COg. 
Reduced  to  a  gray  magnetic  mass. 

In  ignition  tube  with  Na^COa  and  Ch. 

In  flame  on  platinum  wire 


28  BLOWPIPE  ANALYSIS 

With  borax  bead  on  platinum  wire. 
In  O.  F.  colors  very  intensely  blue,  both  hot 
and  cold. 

With  Co(NO3)2 

8.  Copper,  CuO.  —  Before  the  Bp.  on  Ch. 
Fuses   to   a   black   globule,   which   can    be 
reduced  with  some  difficulty. 

Before  the  Bp.  on  Ch.  with  Na2CO3. 
Readily  reduced  to  metallic  bead,  which  is 
red  in  color,  hard,  malleable. 

In  ignition  tube  with  Na2CO3  and  Ch. 

In  flame  on  platinum  wire.  Colors  flame 
emerald-green. 

With  borax  bead  on  platinum  wire.  In 
O.  F.  green  when  hot,  blue  when  cold. 

With  Co(N03)2 

9.  Iron,  Fe203.  —  Before  the    Bp.  on    Ch. 
In    O.  F.    unchanged.       In    R.  F.    becomes 
black  and  magnetic. 


GENERAL  REACTIONS  29 

Before    the    Bp.    on    Ch.   with    Na2CO3 
Reduced  to  a  metallic  powder,  magnetic. 
In  ignition  tube  with  Na2CO3  and  Ch. 

In  flame  on  platinum  wire 

With    borax    bead     on     platinum    wire. 
In  O.  F.  red  while  hot,  yellow  when  cold. 
With  Co(NO3)2 

10.  Lead,  PbO. —  Before  the  Bp.  on  Ch. 
Easily  reduced  to  the  metal,  bead  very 
malleable.  Coating  yellow,  surrounded  by 
white  ring. 

Before  the  Bp.  on  Ch.  with  Na^COg. 
Instantly  reduced.  Coats  the  Ch.  upon 
further  blowing. 

In  ignition  tube  with  Na2CO3  and  Ch. 
Reduced  to  the  metal. 

In  flame  on  platinum  wire.  Tinges 
flame  blue. 

With    borax    bead     on     platinum     wire. 


30  BLOWPIPE  ANALYSIS 

In  O.  F.  dissolves  easily,  forming  a  limpid 
glass. 

With  Co(N03)2 

11.  Manganese,    Mn203. —  Before    the    Bp. 
on  Ch.     At  high  temperature  turns  red. 

Before  the  Bp.  on  Ch.  with  Na2CO3.  Is 
not  reduced. 

Before  the  Bp.  in  O.  F.  on  platinum  foil 
with  -NagCOg.  Transparent  green  mass 
when  hot.  Opaque,  bluish-green  when  cold. 

In  ignition  tube  with  Na2CO3  and  Ch. 
Not  reduced. 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire.  In  O.  F. 
violet-red  while  hot,  amethyst-red  when  cold. 

With  Co(N03)2 

12.  Mercury,    HgO.  —  Before   the    Bp.  on 
Ch.     Instantly  reduced.     Very  volatile. 

Before  the  Bp.  on  Ch.  with  Na2CO3.  Re- 
duced and  volatilized. 


GENERAL  REACTIONS  31 

In  ignition  tube  with  Na.2CO3  and  Ch. 
Sublimes  condensing  in  the  upper  part  of 
the  tube  as  a  metallic  ring  which  is  seen 
with  the  lens  to  consist  of  minute  globules 
of  mercury. 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire 

WithCo(N03)2__ 


13.  Nickel,  NiO.  —  Before  the  Bp.  on  Ch. 
In  O.  F.  unchanged.  In  R.  F.  reduced  to 
metal,  slightly  magnetic. 

Before  the  Bp.  on  Ch.  with  Na2CO8. 
Easily  reduced  to  the  metal. 

In  ignition  tube  with  Na2CO3  and  Ch. 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire.   In  O.F. 
violet  while  hot,  reddish-brown  when  cold. 
With  Co(NO3)2._ 


32  BLOWPIPE  ANALYSIS 

14.  Silver,  AgO.  —  Before  the  Bp.  on  Ch. 
Easily  reduced  to  the  metal.     White,  mal- 
leable, hard  bead.     Coats  the  coal  dark  red 
near  assay. 

Before  the  Bp.  on  Ch.  with  Na2CO3.  In- 
stantly reduced  to  metallic  globule. 

In  ignition  tube  with  Na2CO3  and  Ch. 
Reduced  to  the  metal. 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire.  In 
O.  F.  partially  dissolved.  Bead  becomes 
milk-white. 

With  Co(NO3)2   

15.  Tin,   Sn02.  —  Before  the  Bp.  on  Ch. 
Coats    the    coal    yellow    while    hot,    dirty 
white  when  cool.     Not  reduced. 

Before  the  Bp.  on  Ch.  with  Na2CO3.  Re- 
duced to  metallic  tin.  White,  hard,  mal- 
leable bead.  Coating  white  and  close  to 
assay. 


GENERAL  REACTION'S  33 

In  ignition  tube  with  Na2CO8  and  Ch. 

In  flame  on  platinum  wire  

With  borax  bead  on  platinum  wire.     In 

O.  F.    small    quantity    dissolves    to    limpid 

glass. 

With  Co(NO3)2.     Greenish-blue  color. 

1 6.   Zinc,  ZnO. —  Before  the   Bp.  on   Ch. 

Upon  ignition  becomes  yellow.  Is  not 
reduced. 

Before  the  Bp.  on  Ch.  with  Na2CO3.  Re- 
duced to  metal.  Rapidly  volatilized,  coating 
the  coal  white. 

In  ignition  tube  with   Na2CO3  and   Ch. 

In  flame  on  platinum  wire 

With  borax  bead  on  platinum  wire.  In 
O.F.  yellow  while  hot,  limpid  glass  when 
cold. 

* 

With  Co(NO3)2.     Green  mass. 


34  BLOWPIPE  ANALYSIS 

Having  now  given  the  principal  reactions 
for  the  most  important  metals,  we  will  pro- 
ceed to  the  examination  of  the  alkali  metals, 
the  alkaline  earths,  and  some  of  the  acid 
elements. 

THE  ALKALI  METALS 

17.  Ammonium,  NH4.  —  This  hypotheti- 
cal compound  is  commonly  classed  among 
the  alkali  metals  from  its  close  resemblance 
to  the  members  of  this  group. 

To  detect  the  presence  of  this  hypotheti- 
cal metal,  mix  the  assay  with  about  four 
parts  of  Na2CO3,  place  in  an  ignition  tube, 
and  apply  heat.  The  odor  of  the  evolved 
gas  will  be  recognized,  and  if  a  piece  of 
red  litmus  paper  be  moistened  and  held  at 
the  mouth  of  the  tube,  it  will  be  turned 
blue  by  the  escaping  ammonia  gas. 

We  are  not  authorized  to  infer  the  pre- 
existence  of  ammonium,  however,  from  the 


GENERAL  REACTIONS  3$ 

appearance  of  this  reaction,  for  the  pres- 
ence of  nitrogenous  organic  matter  in  the 
substance,  which  would  be  decomposed  by 
this  treatment,  would  give  rise  to  such  a 
reaction. 

1 8.  Potassium.  —  Potassium  is  recognized 
by  the  color  which  its  salts  impart  to  the 
Bunsen   flame.      If   a   portion   of   a  salt  of 
potassium   be  held  on   a   platinum  wire  in 
the    flame,    it    imparts    a    blue-violet    tint 
which  rapidly  disappears. 

19.  Sodium.  —  Like  potassium,  this  alkali 
metal   is   detected   by   the   color  which   its 
salts  give  to  the  flame. 

If  a  sodium  salt  be  held  on  the  platinum 
wire  in  the  flame,  it  imparts  an  intense 
yellow  color. 

The  extreme  delicacy  of  this  reaction 
has  been  mentioned  elsewhere.  The  value 


36  BLOWPIPE  ANALYSIS 

of  this  test  is  really  lessened  by  its  great 
delicacy,  for  it  is  possible  to  detect  minute 
quantities  of  sodium  in  almost  all  sub- 
stances, although  it  may  not  be  in  chemi- 
cal combination.  As  an  example,  draw  the 
platinum  wire  between  the  fingers,  and 
then  place  in  flame,  and  note  presence  of 
sodium. 

20.  Lithium,  Li20.  —  In  the  Bunsen  flame 
on  the  platinum  wire  it  imparts  a  carmine- 
red  tinge. 

Hydrochloric    acid    on    the    sample   aug- 
ments the  coloration. 

THE  ALKALINE  EARTHS 

21.  Barium,  BaO.  —  In  the  Bunsen  flame 
on  the  platinum  wire  it  imparts  an  apple- 
green  coloration.     This  reaction  is  intensi- 
fied by  moistening  the  sample  with  hydro- 
chloric acid. 


GENERAL  REACTIONS  37 

22.  Calcium,  CaO.  —  In  the  Bunsen  flame 
on  the  platinum  wire  it  imparts  an  orange- 
red   color,  which   appears   gray  when  seen 
through  blue  glass. 

Hydrochloric  acid  on  the  sample  makes 
the  color  more  intense. 

23.  Strontium,    SrO.  —  In     the     Bunsen 
flame  on  the  platinum  wire  it  imparts  an 
intensely  red  color,  which   is  increased   by 
converting  the  substance  into  the  chloride. 

THE  ACID  ELEMENTS 

24.  Borates.  —  If  the  substance  be  finely 
powdered,    moistened    with    glycerine,    and 
then    placed    on    a    platinum    wire    in    the 
Bunsen  flame,  it  imparts  a  brilliant  green 
color. 

If  turmeric  paper  be  dipped  into  a  solu- 
tion of  a  borate,  and  then  be  dried  at 
1 00°  C.,  it  is  turned  to  a  peculiar  red 


38  BLOWPIPE  ANALYSIS 

color.     These  two  reactions  are  extremely 
delicate. 

25.  Bromides.  —  Bromides    treated    with 
microcosmic   salt   and   oxide   of   copper  on 
platinum  wire  impart  to  the  flame  a  greenish- 
blue  color,  the  edges  being  decidedly  green. 

26.  Chlorides.  —  Chlorides  are  treated  in 
the    same    way    as    bromides.     The    color 
imparted  to  the  flame  is  azure-blue. 

To  discriminate  between  bromides  and 
chlorides  more  clearly,  the  substance  is 
mixed  with  anhydrous  potassium  bisulphate 
and  fused  in  an  ignition  tube. 

Bromine  and  sulphur  dioxide  are  evolved 
(if  the  substance  be  a  bromide),  the  tube 
being  filled  with  a  yellow  gas  possessing 
the  characteristic  odor  of  bromine. 

27.  Fluorides.  —  A  small   portion  of   the 
substance  in  a  finely  powdered  condition  is 


GENERAL  REACTIONS  39 

placed  in  one  of  the  ignition  tubes,  a  strip 
of  moist  Brazil-wood  paper  is  introduced 
into  the  open  end,  and  heat  is  applied. 
Hydrofluoric  acid  is  evolved,  and  the  red 
color  of  the  paper  is  changed  into  a  straw- 
yellow. 

Mica,  containing  only  0.75%  of  fluorine, 
shows  the  reaction  clearly. 

28.  Iodides.  —  Iodides  are  treated,  as  the 
bromides  and  chlorides,  in  a  bead  of  micro- 
cosmic    salt    with    oxide    of    copper.     The 
flame  is  colored  green. 

Fused  with  potassium  bisulphate  in  an 
ignition  tube  the  violet  vapors  of  iodine 
are  evolved,  and  thus  iodides  may  be  dis- 
tinguished from  chlorides  and  bromides. 

29.  Nitrates.  —  If    a    nitrate    be    heated 
upon  charcoal  before  the  Bp.,  violent  defla- 
gration occurs.      If  the  substance  contain- 


40  BLOWPIPE  ANALYSIS 

ing  the  nitric  acid  be  mixed  with  a  very 
small  quantity  of  finely  powdered  potas- 
sium cyanide,  the  deflagration  is  accom- 
panied with  ignition  and  detonation. 

If  the  substance  be  mixed  in  a  dry 
condition  with  dry  potassium  bisulphate, 
and  is  then  heated  in  an  ignition  tube, 
red-brown  nitrous  fumes  are  evolved.  This 
reaction  takes  place  if  there  is  but  a  small 
quantity  of  nitrate  present. 

30.  Phosphates.  —  Phosphates   impart   to 
the  flame  a  bluish  green  color.     The  color 
is   made   more   intense   by   moistening   the 
substance   with    sulphuric    acid,    and    then 
taking   the   paste  so   formed  on    the   plati- 
num wire   and    placing   it    in    the    Bunsen 
flame. 

31.  Silicates.  —  Silicates,    when    treated 
with  microcosmic  salt  on  a  platinum  wire, 


GENERAL  REACTIONS  41 

suffer  decomposition;  the  bases  unite  with 
the  phosphoric  acid  to  form  a  transparent 
glass  in  which  the  silica  may  be  seen  float- 
ing as  a  cloudy  mass. 

The  bead  must  only  be  examined  for 
silica  while  hot,  since  on  cooling  it  becomes 
opaque. 

32.  Sulphides.  —  Many  sulphides,  when 
heated  in  an  ignition  tube,  volatilize  and 
give  a  sublimate  of  sulphur  in  combina- 
tion with  the  metallic  portion  of  the  sub- 
stance. 

A  very  delicate  test  for  sulphur  in  what- 
ever combination  it  may  be  found  in  a  sub- 
stance, and  which  may  be  performed  with 
great  ease,  is  to  mix  the  finely  powdered 
assay  with  four  parts,  Na2CO3,  and  fuse  in 
an  ignition  tube.  When  thoroughly  fused 
the  tube  is  broken,  and  the  fused  mass  is 
placed  on  a  bright  silver  coin,  and  a  drop 


42  BLOWPIPE  ANALYSIS 

of  water  is  added.  If  the  substance  con- 
tains sulphur,  a  black  spot  will  be  observed 
on  the  coin  where  the  fused  mass  was 
placed. 

Before  going  on  to  the  next  chapter,  the 
student  should  assure  himself  of  his  famil- 
iarity with  the  reactions  just  given,  and  he 
should  practise  with  various  substances,  the 
nature  of  which  is  unknown  to  him. 


CHAPTER   IV 

BEHAVIOR  OF  SOME  OF  THE  PRINCIPAL  ORES 
BEFORE  THE  BLOWPIPE 

FOR  the  sake  of  practice,  and  as  a  fitting 
introduction  to  "  Determinative  Mineralogy," 
this  chapter  is  appended.  It  is  not  intended 
to  give  a  detailed  account  of  the  minerals, 
but  rather  to  set  before  the  student  the 
most  marked  characters,  such  as  hardness, 
specific  gravity,  color,  lustre,  etc. 

To  determine  the  hardness  of  a  mineral, 
we  try  to  scratch  it  with  the  minerals 
forming  an  arbitrary  "scale  of  hardness," 
proceeding  successively  from  the  softest  to 
the  hardest.  When  we  say  that  a  certain 
mineral  has  hardness  =  4,  we  mean  that  the 
mineral  is  scratched  by  4  on  the  scale,  and 

43 


44  BLOWPIPE  ANALYSIS 

that  4  on  the  scale  is  scratched  by  the 
mineral.  The  scale  of  hardness  chiefly  in 
use  is  the  Mohs-Breithaupt  scale,  which  is 
as  follows:  — 

1.  Talc,  common  laminated  light  green 
variety. 

2.  Gypsum,  crystallized. 

3.  Calcareous  spar,  transparent  variety. 

4.  Fluor  spar,  crystalline. 

5.  Apatite,  transparent. 

6.  Orthoclase,  white  cleavable  variety. 

7.  Quartz,  transparent. 

8.  Topaz,  transparent. 

9.  Sapphire,  cleavable  variety. 
10.    Diamond. 

It  seldom  happens  in  determining  the 
hardness  of  a  mineral  that  its  hardness  ex- 
actly conforms  to  that  of  some  one  member 
of  the  scale.  In  such  cases  we  generally 
estimate  the  hardness.  For  example,  sup- 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE    45 

pose  a  mineral  was  harder  than  4,  but 
softer  than  5,  and  that  it  was  nearer  5 
than  4,  then  we  would  call  its  hardness  4^. 

In  order  to  preserve  the  scale  some 
operators  use  a  three-cornered  file,  first 
cutting  the  mineral  and  then  the  scale 
until  a  number  is  found,  which  is  abraded 
to  about  the  same  depth  as  the  mineral 
under  examination. 

Since  a  set  of  minerals  forming  a  scale 
of  hardness  is  not  always  at  hand,  the 
following  scale  given  by  Chapman  is 
appended : — 

1.  Yields  easily  to  the  nail. 

2.  Yields  with   difficulty  to   the    nail   or 
just  receives  an  impression  from  it.     Does 
not  scratch  a  copper  coin. 

3.  Scratches  a  copper   coin   but   is   also 
scratched    by  it,  being  of   about  the  same 
degree  of  hardness. 


46  BLOWPIPE  ANALYSIS 

4.  Not  scratched  by  a  copper  coin.     Does 
not  scratch  glass. 

5.  Scratches  glass  with  difficulty,  leaving 
its  powder  on  it.    Yields  readily  to  the  knife. 

6.  Scratches    glass    easily.      Yields    with 
difficulty  to  the  knife. 

7.  Does  not  yield  to  the  knife.     Yields 
to  the  edge  of  a  file,  though  with  difficulty. 

8.  9,   10.    Harder  than  flint. 

Specific  gravity  cannot  well  be  deter- 
mined without  the  aid  of  a  balance,  and 
hence  its  value  here  is  not  great. 

As  in  the  preceding  chapter,  alphabetic 
arrangement  will  be  employed. 

ORES  OF  ANTIMONY 

Stibnite,  Sb2S3,  Sb.;i,  S.29.  —  *H  =  2, 
0  =  4.52—4.62.  Of  lead-gray  color  and 
metallic  lustre.  Consists  of  a  large  number 

*  H  =  Hardness,  G  =  Specific  Gravity. 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE    47 

of  needle-shaped  crystals.  Brittle.  Fuses 
in  candle  flame.  In  an  ignition  tube  yields 
a  sublimate  of  sulphur.  On  Ch.  before  the 
Bp.  it  is  volatilized,  giving  antimony  coating 
and  tinges  the  flame  pale  blue. 

ORES  OF  ARSENIC 

Native  Arsenic,  As.  —  This  contains  traces 
of  Sb,  Ag,  Fe,  Co,  and  Ni. 

H  =  3-5>  0  =  5.7-5.8.  Dark  gray  in 
color.  Fracture  tin-white,  tarnishing  rap- 
idly. Volatilizes  before  the  Bp.  on  Ch. 
without  melting,  giving  white  coating  of 
arsenious  acid  and  characteristic  garlic  odor. 
In  ignition  tube  it  sublimes,  giving  arsenical 
ring. 

Realgar,  AsS,  As .  70,  S  .  30. —  H  =  1.5  —  2, 
0  =  3.56.  Bright  red  to  orange-red  color 
and  resinous  lustre.  In  an  ignition  tube 
it  fuses  and  finally  sublimes.  The  sub- 


48  BLOWPIPE  ANALYSIS 

limate  when  cool  is  red  and  transparent. 
Fuses  readily  before  the  Bp.  on  Ch.  and 
burns  with  -  pale  yellowish  flame,  emitting 
gray-white  fumes  having  garlic  odor. 

Orpiment,  As2S3,  As .  61,  S  .  39. — 
H  =  1.5 -2.0,   0=3.4-3.5. 

Lemon-yellow  in  color  and  resinous  or 
pearly  lustre.  Sectile.  Before  the  Bp.  on 
Ch.  behaves  like  realgar,  but  in  an  ignition 
tube  it  gives  a  dark  yellow  sublimate  which 
is  transparent. 

ORES  OF  BISMUTH 

Native  Bismuth,  Bi.  —  This  contains  traces 
of  As,  Te,  and  S. 

H  =  2.0  -  2.5,  G  =  9.7  -  9.83.  Color,  silver- 
white,  slightly  tinged  with  red.  Metallic 
lustre.  Brittle  when  cold,  but  may  be  lami- 
nated when  hot.  Before  the  Bp.  on  Ch. 
behaves  like  pure  Bi. 


PRINCIPAL   ORES  BEFORE  THE  BLOWPIPE    49 

Bismuthite,  Bi2O3 . 90,  CO2 .  7,  H2O  .  3,  — 
H  =  4.0 -4.5,    0  =  6.9-7.8. 

Usually  of  a  white  or  light  greenish  color 
and  vitreous  lustre,  in  acicular  crystalliza- 
tions. In  an  ignition  tube  decrepitates, 
yielding  water  and  turning  gray.  Before 
the  Bp.  on  Ch.  it  fuses  easily  and  is  reduced 
to  metallic  globule,  coating  the  Ch.  with 
Bi2O3.  With  Na2CO3  it  occasionally  gives 
the  sulphur  reaction. 

ORES  OF  CHROMIUM 

Chromic  Iron  Ore,  FeO.32,  Cr2O8.68. — 
A12O3,  Fe2O3,  MnO,  and  MgO  are  commonly 
present.  H  =  5.5,  0  =  4.32-4.57.  Occurs 
usually  massive.  Color,  iron-black  to  brown- 
ish black.  In  many  varieties  strongly  mag- 
netic. Lustre,  shining  and  somewhat  me- 
tallic. Heated  in  an  ignition  tube,  remains 
unchanged.  Infusible  before  the  Bp.  on  Ch. 


50  BLOWPIPE  ANALYSIS 

Before  the  Bp.  on  Ch.  with  Na2CO3  and 
KCN  yields  metallic  iron.  In  borax  bead 
it  slowly  dissolves  to  a  clear  transparent 
glass,  which  is  a  beautiful  green  when  cool. 

ORES  OF  COBALT 

Smaltite,  Co(Fe,  Ni)  As2,  Co .  28,  As .  72. 
—  H  =  5.5,  G  =  6.37  -  7.30.  Color,  tin-white 
or  steel-gray.  Lustre,  metallic.  When 
heated  to  redness  in  an  ignition  tube  it 
yields  a  sublimate  of  metallic  arsenic.  Before 
the  Bp.  on  Ch.  it  fuses  readily,  with  emis- 
sion of  arsenical  fumes,  to  a  grayish  black 
magnetic  globule.  This  globule  may  be 
examined  for  iron,  cobalt,  and  nickel  with 
the  borax  bead. 

Cobaltite,  CoS2  +  Co  As2,  Co.  36,  As.  45, 
8.19. —  H  =  5.5,  0  =  6.0-6.3.  Color,  silver- 
white  tinged  with  red.  Metallic  lustre. 
Before  the  Bp.  on  Ch.  fuses  easily,  with 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE     5 1 

emission  of  copious  arsenical  fumes,  to  a 
gray  magnetic  globule.  Remains  unchanged 
in  the  ignition  tube. 

Linnaeite,  (Co,  Ni)3S4,  (Co,  Ni)s8,  8.42.— 
H  =  5«5,  0  =  4.8-5.0.  Color,  bright  steel- 
gray,  sometimes  reddish.  Lustre,  metallic. 
Crystallizes  in  the  regular  octahedron. 
Before  the  Bp.  on  Ch.  fuses  to  a  metallic 
globule  which  is  attracted  by  the  magnet. 
With  borax  bead  gives  reaction  for  cobalt. 

Erythrite,   Co3O8As2  +  8  H2O, 
CoO.37.6,  H2O.24.o.— 

H=  1.5 -2.0,  0=2.95. 

Color,  crimson  to  peach-red.  When  crys- 
tallized, of  pearly  lustre,  but  frequently  dull 
and  earthy.  Heated  in  ignition  tube  gives 
off  water,  and  color  changes  to  blue  or 
green.  Before  the  Bp.  on  Ch.  in  R.  F.  it 


52  BLOWPIPE  ANALYSIS 

emits  arsenical  fumes  and  melts  to  a  dark 
gray  globule  which  with  the  borax  bead 
reacts  for  cobalt. 

ORES  OF  COPPER 
Native  Copper,  Cu.  — 

H  =  2.5-3,   0  =  8.5-8.9. 

Color,  copper-red.  Lustre,  metallic.  Oc- 
curs usually  massive  and  very  arborescent. 
Before  the  Bp.  on  Ch.  it  fuses,  and  if 
the  heat  is  sufficiently  high  it  assumes  a 
bright  bluish-green  surface ;  on  cooling  it 
is  covered  with  a  coat  of  black  oxide.  In 
the  borax  bead  it  reacts  for  copper. 

Chalcopyrite,  CuFeS2,  Cu  .  35,  Fe  .  30, 
8.35.— H  =  3.5 -4,  0  =  4.1-4.3.  Color, 
brass-yellow,  often  golden-yellow.  Lustre, 
metallic.  Occurs  crystallized,  but  is  gener- 
ally found  massive.  Is  easily  scratched 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE      53 

with  a  knife.  Heated  in  an  ignition  tube 
decrepitates,  and  occasionally  yields  a  faint 
sublimate  of  sulphur.  Before  the  Bp.  on 
Ch.  it  blackens,  but  becomes  red  again  on 
cooling.  Before  the  Bp.  on  Ch.  with  Na2CO3 
and  KCN  it  is  reduced,  and  the  metals  are 
obtained  in  separate  masses.  It  reacts  with 
the  borax  bead  for  copper  and  iron. 

Copper  Glance,  Cu2S,  Cu  .80,  S .  20.  — 
H  =  2.5  -  3.0,  G  =  5.5  -  5.8.  Color,  dark 
blue  to  steel-gray.  Occurs  in  compact 
masses,  often  very  shining.  Before  the  Bp. 
on  Ch.  fuses  to  a  globule  which  boils 
and  emits  glowing  drops.  Sulphur  dioxide 
escapes  abundantly,  and  the  outer  flame  is 
colored  blue.  Before  the  Bp.  on  Ch.  with 
Na2CO3  yielding  a  metallic  globule. 

Tetrahedrite,  4  CuS  +  Sb2S3.  —  Frequently 
contains  silver,  iron,  mercury,  and  zinc. 


54  BLOWPIPE  ANALYSIS 

H  =  3.0 -4.0,  0  =  4.5-5.  Color,  steel-gray 
to  iron-black.  Heated  in  an  ignition  tube 
fuses  and  gives  a  sublimate  of  antimonious 
oxide.  When  mercury  is  present  this  con- 
denses in  the  upper  part  of  the  tube,  form- 
ing the  characteristic  mirror.  Before  the 
Bp.  on  Ch.  it  fuses  readily  to  a  metallic 
globule,  emitting  dense  white  fumes ;  zinc 
and  antimony  coatings  are  deposited  on  the 
Ch.  After  long  ignition  before  the  Bp.,  if 
the  mineral  is  finely  powdered  and  mixed 
with  Na2CO3  and  KCN,  the  ore  is  reduced 
to  the  metal. 

Cuprite,  Cu2O,  Cu . 89,  0 .  1 1.  — 
H  =  3.5  -4.0,   0  =  5.5-6.15. 

Color,  intense  crimson-red.  Before  the  Bp. 
on  Ch.  blackens  and  fuses  quietly,  and  finally 
yields  a  metallic  globule  of  copper.  Before 
the  Bp.  on  Ch.  with  Na2CO3  and  KCN  it 
is  easily  reduced. 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE      55 

Malachite,    2  CuO  +  CO2+  H2O,  CuO  .  72, 
CO2.20,  H2O.8.— 

H  =  3.5 -4.0,   0=3.90-4.03. 

Color,  bright  green.  Occurs  generally  in 
mammillated  concretions.  Lustre,  shining 
and  fracture,  silky.  Heated  in  an  ignition 
tube  yields  water  and  blackens.  Before  the 
Bp.  on  Ch.  it  fuses  to  a  metallic  globule. 
Before  the  Bp.  on  Ch.  with  Na2CO3  and 
KCN  it  is  easily  reduced.  With  borax 
bead  gives  characteristic  coloration. 

Azurite,    3  CuO +  2  CO2+  H2O,    CuO  .  69, 
C02.26,  H20.5.— 

H  =  3.5 -4.0,   0=3.77-3.83. 

Color,  azure-blue.  Occurs  usually  in  crys- 
tallized or  globular  masses.  Lustre,  earthy 
or  vitreous.  Before  the  Bp.  and  with  other 
reagents  behaves  like  malachite. 


56  BLOWPIPE  ANALYSIS 

Chrysocolla  CuO  +  SiO2  +  2  H2O, 
CuO.45.3,  H2O.20.5.  —  H  =  2.0- 3.0,  G=2. 
Color,  bluish-green,  closely  resembling  mala- 
chite. Occurs  usually  as  an  incrustation, 
its  surface  being  very  smooth,  like  enamel. 
In  an  ignition  tube  it  blackens  and  yields 
water.  Before  the  Bp.  on  Ch.  in  O.  F.  it 
blackens,  coloring  the  flame  bright  green; 
in  the  R.  F.  it  turns  red.  Before  the  Bp. 
on  Ch.  with  Na-jCO3  yields  metallic  copper. 
In  borax  bead  it  reacts  for  copper. 

Atacamite,     CuCl2  +  3  CuO2H2  -  Cl .  16.6, 
0 . 20.3,  Cu .  50. i ,  H2O  .  1 3.0.  — 

H  =  3.0 -3.5,    G=  3.75  -3.77. 

Color,  green  to  blackish  green.  Lustre, 
adamantine  to  vitreous.  In  an  ignition 
tube  yields  water.  Before  the  Bp.  on  Ch. 
colors  flame  blue.  Before  the  Bp.  on  Ch. 
with  Na2CO3  and  KCN  is  reduced  to  the 
metal.  In  borax  bead  it  reacts  for  copper. 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE     S7 

ORES  OF  IRON 

Limonite,  2  Fe2O3  +  3  H2O,  Fe2O8 .  86, 
H2O  .  14.  —  H  =  5.0-5.5,  G  =  3.6  -  4.0. 
Color,  brown  to  ochre-yellow.  Earthy  or 
semi-metallic  in  appearance.  In  an  igni- 
tion tube  yields  water.  Before  the  Bp. 
on  Ch.  infusible.  In  borax  bead  reacts  for 
iron. 

Hematite,  Fe,O3,  Fe .  70,  0 .  30.  — 
H  =  5-5  -6-5,   0  =  4.9-5.3. 

Color,  dark  steel-gray  to  iron-black.  Lustre, 
metallic.  When  pulverized  yields  a  red 
powder.  Before  the  Bp.  on  Ch.  infusible. 
After  long  roasting  becomes  magnetic.  In 
borax  bead  gives  usual  indications  of  iron. 

Magnetite,  Fe3O4,  FeO  .31,  Fe2O3 . 69.  — 
H  =  5-5 -6.5,   0=5.17-5.18. 


58  BLOWPIPE  ANALYSIS 

Color,  iron-black.  Lustre,  shining  and  me- 
tallic. Pulverized,  its  powder  is  black.  It 
is  strongly  magnetic.  Fuses  with  difficulty 
before  the  Bp.  on  Ch.  In  borax  bead  reacts 
for  iron. 

Pyrites,  FeS2,  Fe  .  47,  S  .  53.— 

H  =  6.0  -  6.5,  G  =  4.95  -  5.20. 
Color,  brass-yellow.  Lustre,  metallic.  Oc- 
curs commonly  in  cubes.  It  often  con- 
tains small  quantities  of  Au,  Ag,  Cu,  As, 
Co,  and  Mn.  Heated  in  an  ignition  tube 
gives  a  sublimate  of  sulphur,  the  residue 
becoming  magnetic.  Before  the  Bp.  on 
Ch.  in  O.  F.  sulphur  is  burned  off  and 
the  red  oxide  remains.  This  residue  may 
then  be  examined  for  iron,  etc. 

Marcasite  (White  Iron  Pyrites). —  Having 
the  same  general  composition  as  pyrite,  but 
much  lighter  in  color.  Crystals,  prismatic. 
Before  the  Bp.  on  Ch.  behaves  like  pyrite. 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE     59 

Pyrrhotite,  Fe7S8,  Fe.6o.5,  8.39.5.— 
H  =  3.5 -4.5,   0  =  4.58-4.64. 

Color,  bronze-yellow.  Closely  resembles 
pyrite,  but  may  be  distinguished  from  it 
by  being  feebly  magnetic.  Heated  in  an 
ignition  tube  yields  no  sublimate.  Before 
the  Bp.  on  Ch.  fuses  to  a  magnetic  globule, 
which  exhibits  a  yellowish  crystalline  struc- 
ture when  fractured. 

Mispickel,  FeAsS,  Fe.34,  As. 46,  8.20. — 
H  =  5.5~6.o,  G  =  6.0 -6.2.  Color,  silver- 
white.  Lustre,  metallic;  very  brittle.  Often 
associated  with  it  we  find  small  quantities 
of  Co,  Ag,  and  Au.  Heated  in  an  igni- 
tion tube  it  first  yields  a  red  sublimate  of 
sulphide  of  arsenic,  and  then  afterward 
a  crystalline  sublimate  of  metallic  arsenic. 
Before  the  Bp.  on  Ch.  emits  dense  fumes 
of  arsenic  and  deposits  a  coating  on  the 


60  BLOWPIPE  ANALYSIS 

coal;    it    then    fuses    to    a   globule    which 
behaves  like  pyrrhotite. 

Siderite,  FeCO3,  FeO.62,  CO2.38.— 
H  =  3.5 -4.5,  0=3.7-3.9.  Color,  grayish 
yellow  to  reddish  brown.  Lustre,  pearly. 
Crystallizes  in  rhombohedrons  with  curved 
faces ;  these  crystals  are  distinctly  cleavable 
and  massive.  Heated  in  an  ignition  tube 
it  decrepitates  with  evolution  of  carbon 
dioxide.  Before  the  Bp.  on  Ch.  infusible. 
Before  the  Bp.  on  Ch.  with  Na2CO3  it  fuses 
to  a  magnetic  mass.  With  borax  bead  it  re- 
acts for  iron  and  sometimes  for  manganese. 

ORES  OF  LEAD 
Galena,  PbS,  Pb .  87,  S  .  1 3.  — 
H  =  2.5,   0=7.4-7.6. 

Color,  bluish  gray,  slowly  tarnishing.     Lus- 
tre, metallic.     Crystals  in  the  form  of  cubes. 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE     6 1 

Heated  in  an  ignition  tube  it  sometimes 
decrepitates  and  yields  a  sublimate  of  sul- 
phur. Before  the  Bp.  on  Ch.  easily  reduced 
to  the  metallic  state,  the  Ch.  becoming 
coated  with  sulphate  and  oxide  of  lead. 
The  metallic  globule  usually  contains  a 
little  silver.  To  separate  this,  the  process 
known  as  "cupellation"  is  employed.  A  hole 
is  bored  into  the  Ch.  about  i  cm.  in  diame- 
ter and  about  6  mm.  deep.  Into  this  hole 
is  placed  a  stiff  paste  made  by  mixing  finely 
pulverized  bone-ash  with  a  little  soda  and 
water.  This  paste  is  pressed  in  hard,  and 
then  the  surface  is  smoothed  off,  and  the 
centre  is  slightly  depressed  with  the  rounded 
end  of  a  glass  rod.  The  charcoal  so  pre- 
pared is  set  in  a  warm  place  to  allow  the 
paste  to  dry.  When  the  paste  is  quite 
dry  the  small  globule  of  lead  is  placed  in 
the  depression  in  the  centre  of  the  bone- 
ash  "cupel,"  and  is  there  exposed  to  the 


62  BLOWPIPE  ANALYSIS 

O.  F.  from  the  Bp.  The  lead  is  oxidized 
and  is  absorbed  by  the  bone-ash,  while  any 
silver  present  will  remain  in  the  central 
depression  as  a  bright  shining  bead. 

Cerusite,  PbCO3,  PbO .  84,  CO2.i6.— 
H  =  3.0 -3.5,  0  =  6.46-6.57.  Color,  white, 
gray,  or  yellow.  Lustre,  adamantine.  Crys- 
tallizes in  prismatic  needles  When  heated 
in  an  ignition  tube  carbon  dioxide  is  evolved 
and  the  residue  turns  yellow.  Before  the 
Bp.  on  Ch.  readily  reduced  to  metallic 
lead. 

Anglesite,  PbSO4,  PbO .  74,  SO3.26.— 
H  =  2.0—3.0,  0  =  6.12  —  6.39.  Color,  yel- 
low, gray,  and  brown.  Lustre,  adamantine, 
resinous.  Heated  in  an  ignition  tube 
decrepitates,  and  sometimes  yields  a  little 
water.  Before  the  Bp.  on  Ch.  fuses  to 
a  clear  bead,  which  on  cooling  becomes 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE     63 

opaque.  Before  the  Bp.  on  Ch.  with 
Na2CO3  is  reduced  to  the  metal  giving  a 
yellow  coating.  The  Na^Og  absorbed  by 
the  coal  reacts  for  S. 

ORES  OF  MANGANESE 

Pyrolusite,  MnO2,  Mn .  63.2,  O  .  36.8.  — 
H  =  2.0—2.5,  0  =  4.82.  Color,  iron-black  to 
steel-gray.  Lustre,  non-metallic.  Heated 
in  an  ignition  tube  yields  generally  a  little 
water,  and  if  the  temperature  be  high 
enough,  oxygen  is  evolved.  Before  the 
Bp.  on  Ch.  infusible.  In  borax  bead  gives 
characteristic  color. 

Psilomelane,  Mn2O8  +  H2O.  — 

H  =  5.5 -6.0,   0=3.7-4.7. 

Color,  iron-black  to  steel-gray.  Generally 
resembles  pyrolusite,  but  is  distinguished 
from  it  by  its  superior  hardness.  It  fre- 


64  BLOWPIPE  ANALYSIS 

quently  contains  BaO  and  Li2O.    It  behaves 
before  the  Bp.  like  pyrolusite. 

Wad  (Bog  Manganese).  —  This  mineral  is 
essentially  MnO2,  MnO,  and  H2O,  with 
small  quantities  of  Fe2O3,  A12O3,  BaO,  SiO2, 
etc.,  associated  with  it. 

H  =  0.5 -6.0,  0  =  3.0-4.2.  Color,  dull 
black.  Heated  in  an  ignition  tube  yields 
water  in  abundance,  otherwise  it  behaves 
like  pyrolusite. 

ORES  OF  MERCURY 

Native  Mercury,  Hg.  —  G  =  13.5  —  13.6. 
Color,  silver-white.  Is  liquid  at  all  ordi- 
nary temperatures.  Heated  in  an  ignition 
tube  is  volatilized,  the  vapors  condensing 
in  the  upper  end  of  tube  to  small  metallic 
globules  of  Hg.  Before  the  Bp.  on  Ch.  it 
is  volatilized.  Frequently  contains  Ag. 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE    65 

Cinnabar,  HgS2,  Hg.86,  S.  14. — 
H  =  2.0 -2.5,    G  =  8.0 -8.2. 

Color,  scarlet-red  to  brick-red.  Lustre,  non- 
metallic.  When  pulverized  yields  a  powder 
of  vermilion-red  color.  Heated  in  an  ig- 
nition tube  it  volatilizes,  yielding  a  black 
sublimate,  which  by  friction  becomes  red. 
Before  the  Bp.  on  Ch.  it  is  wholly  vola- 
tilized. Heated  in  an  ignition  tube  with 
Na2CO3  metallic  mercury  sublimes,  con- 
densing in  the  upper  portion  of  the  tube 
in  minute  globules. 

ORES  OF  NICKEL 

Millerite,  NiS,  Ni.644,  $.35.6.— 
H  =  3.0 -3.5,  0=5.2-5.6. 

Color,  brass-yellow.  Brittle.  Before  the 
Bp.  on  Ch.  it  fuses  to  a  magnetic,  metallic 
globule.  The  roasted  mineral  gives  in  the 
borax  bead  the  color  reaction  characteristic 


66  BLOWPIPE  ANALYSIS 

of  nickel,  and  sometimes  that  of  cobalt, 
which  is  often  associated  with  it. 

Niccolite,  NiAs,  Ni .  44,  As .  56.  — 
H  =  5.0 -5.5,  G=  7.35  -7.67. 

Color,  pale  copper-red.  Lustre,  metallic. 
Very  brittle.  Heated  in  an  ignition  tube 
yields  a  copious  sublimate  of  arsenious 
oxide,  the  residue  falling  to  a  greenish 
powder.  Before  the  Bp.  on  Ch.  fuses  to  a 
white  brittle  globule  emitting  arsenical 
fumes.  In  borax  bead  gives  color  character- 
istic of  nickel.  Frequently  in  this  mineral 
a  portion  of  the  arsenic  is  replaced  by 
antimony. 

ORES  OF  SILVER 
Native  Silver,  Ag.  — 

H  =  2.5  — 3.0,  G=IO.I  —  n.o. 
Color,  silver-white.     Lustre,  metallic.     Duc- 
tile  and    malleable.      Usually   occurs    asso- 


PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE    6/ 

ciated  with  Au,  As,  Sb,  Cu,  Fe,  etc. 
Before  the  Bp.  on  Ch.  easily  fuses  to  a 
globule  which  is  surrounded  with  a  dark 
red  coating  on  the  coal. 

^ 

Argentite,  Ag.2S,  Ag.S/.i,  S.  12.9. — 
H  =  2.0  — 2.5,  0=7.20-7.36. 

Color,  blackish  lead-gray.  Lustre,  metallic. 
Very  sectile.  Before  the  Bp.  on  Ch.  in 
O.  F.  intumesces  with  evolution  of  sulphur 
dioxide,  finally  yielding  a  metallic  globule 
of  Ag. 

Pyrargyrite,  Ag3SbS3,  Ag.59.8,  Sb.22.5, 
8.17.7.— H  =  2.5,  0=5.77-5.86.  Color, 
black  to  dark  cochineal-red.  Lustre,  metal- 
lic, adamantine.  In  an  ignition  tube  it 
yields  on  continued  heating  a  sublimate  of 
antimony  sulphide.  Before  the  Bp.  on  Ch. 
it  gives  a  coating  of  antimony  trioxide. 


68  BLOWPIPE  ANALYSIS 

Before    the    Bp.   on    Ch.   with    Na2CO3    is 
reduced  to  metallic  silver. 

Proustite,  Ag3S3As,  Ag.65.5,  As.  15.1, 
S.  194.—  H  =  2.0 -2.5,  0=5.57-5.64. 
Color,  light  red.  Lustre,  splendent,  adaman- 
tine. Before  the  Bp.  on  Ch.  it  behaves  like 
pyrargyrite,  save  that  it  gives  off  arsenical 
fumes  instead  of  antimonious  oxide. 

Stephanite,  Ag5S4Sb,  Ag.68.5,  Sb.is.3, 
S  .  16.2. —  H  =  2.0  —  2.5,  G  =  6.2  —  6.3.  Color, 
iron-black  to  blackish  gray.  Lustre,  me- 
tallic. Very  brittle  and  fragile.  In  an  ig- 
nition tube  it  decrepitates,  fuses,  and  finally 
yields  a  slight  sublimate  of  antimony  tri- 
sulphide.  Before  the  Bp.  on  Ch.  gives  a 
coating  of  antimonious  oxide.  Before  the 
Bp.  on  Ch.  with  Na2CO3  a  globule  of 
metallic  silver  is  obtained.  The  mineral 
frequently  contains  copper  and  iron. 


PRINCIPAL   ORES  BEFORE  THE  BLOWPIPE    69 

Kerargyrite,  AgCl,  Ag.75«3,  0.24.7.— 
H  =1.0—1.5,  0=5.52.  Color,  white,  gray, 
yellowish,  greenish  to  blue.  Lustre,  resin- 
ous, adamantine.  Soft  like  wax.  Fuses 
easily  in  a  candle-flame.  Before  the  Bp. 
on  Ch.  it  is  readily  reduced  to  metallic 
silver. 

ORES  OF  TIN 

Cassiterite,  SnO2,  Sn.79,  O.2i. — 
H  =  6.0 -7.0,  0  =  6.8-7.0. 

Color,  brown,  black.  Lustre,  adamantine, 
brilliant.  Occurs  crystallized  in  square 
prisms.  Reentrant  angles  characteristic. 
Before  the  Bp.  on  Ch.  with  Na2CO3  and 
KCN  reduced  to  a  metallic  globule  of  tin. 
In  the  borax  bead  gives  characteristic  re- 
action. 

Stannite,  2  Cu2S  .  SnS2  +  2  (FeS  .  ZnS) 
Sn  .  S2. —  H  =  4.0,  G  =  4.3  —  4.5.  Color, 


70  BLOWPIPE  ANALYSIS 

steel-gray  to  iron-black.  Lustre,  metallic. 
Occurs  usually  massive  and  disseminated. 
Heated  in  an  ignition  tube  it  yields  sul- 
phur dioxide.  Before  the  Bp.  on  Ch.  it 
emits  sulphur  dioxide  and  becomes  cov- 
ered with  oxide  of  tin.  Before  the  Bp.  on 
Ch.  with  Na2CO3  and  KCN  it  gives  an 
impure  globule  of  copper.  A  very  difficult 
mineral  to  determine. 

ORES  OF  ZINC 

Calamine,  H2Zn2O5Si,  SiO2.25.o,  ZnO. 
67.5,  H2O.7.5.—  H  =  4.5 -5.0,  0=34-3.5. 
Color,  white,  gray,  bluish,  or  brown.  Lustre, 
vitreous.  Brittle.  In  an  ignition  tube 
yields  water  when  heated  and  becomes 
milky  white.  Before  the  Bp.  on  Ch.  prac- 
tically infusible.  With  Co(NO3)2  it  assumes 
a  green  color  which  passes  into  a  fine  blue 
when  the  heat  is  increased. 


PRINCIPAL   ORES  BEFORE  THE  BLOWPIPE    71 

Smithsonite, 

Zn .  CO3,  ZnO .  64.8,  CO2 .  35.2.  — 

H  =  5,  0  =  4.30-445.  Color,  gray,  yellow, 
brown,  and  green.  Lustre,  vitreous,  pearly. 
Heated  in  an  ignition  tube  CO2  is  evolved, 
residue  appearing  white.  It  often  contains 
impurities  of  Cd,  Pb,  Fe,  Mn,  Ca,  and  Mg. 
When  these  are  present  the  residue  in  the 
ignition  tube  becomes  dark  on  cooling. 
Before  the  Bp.  on  Ch.  with  Na2CO3  and 
exposed  to  the  R.  F.  it  is  decomposed.  It 
gives  the  characteristic  reaction  for  zinc 
with  Co(NO3)2. 

Zincite,  ZnO,  Zn .  80.3,  0 . 19.7. — 
H  =  4.0 -4.5,  0  =  5.43-5.70. 

Color,  blood-red.  Lustre,  brilliant,  sub- 
adamantine.  Before  the  Bp.  on  Ch.  infusible. 
Before  the  Bp.  on  Ch.  with  Na2CO3  gives 
coating  of  zinc  oxide.  Oives  characteristic 


72  BLOWPIPE  ANALYSIS 

reaction  with  Co(NO3)2.  It  frequently  con- 
tains a  small  quantity  of  Mn2O3,  which  may 
be  detected  in  the  borax  bead. 

Sphalerite,  ZnS,  Zn .  67,  S  .  33. — 
H  =  3-5-4-0,  0=3.9-4.1. 

Color,  yellow  to  black.  Lustre,  resinous,  brill- 
iant, and  sometimes  submetallic.  Heated 
in  an  ignition  tube  sometimes  decrepitates. 
Before  the  Bp.  on  Ch.  infusible.  Before  the 
Bp.  on  Ch.  with  Na2CO3  easily  reduced. 
With  Co(NO8)2  gives  the  characteristic  re- 
action. It  frequently  contains  small  quan- 
tities of  Cd,  Hg,  Sn,  Pb,  Au,  Ag,  etc. 


PRINCIPAL   ORES  BEFORE  THE  BLOWPIPE     73 


TABLE  OF  COLORS  OF  COATINGS  ON  CHARCOAL 


ELEMENT 

COLOR  HOT 

COLOR  COLD 

Antimony 
Arsenic 
Bismuth 
Cadmium 

(Rather  volatile) 
(Very  volatile) 
Orange-Yellow 
Brownish  Yellow 

White 
White 
Lemon-Yellow 
Reddish  Brown 

Lead 
Silver 

Lemon-  Yellow  (volatile) 
Dark  Red 

Lemon-Yellow 
Dark  Red 

Tin 

Faint  Yellow 

White 

Zinc 

Yellow 

White 

II 


TABLE  OF  FLAME  COLORATIONS 


RED 

YELLOW 

GREEN 

Calcium 

Sodium 

Barium 

Lithium 

Boron 

Strontium 

Iodine 

BLUISH  GREEN 

BLUE 

VIOLET 

Bromine 

Chlorine 

Potassium 

Copper 

Phosphorus 

74 


BLOWPIPE  ANALYSIS 


III 


TABLE  OF  COLORS  OF  BORAX  BEADS  IN  OXIDIZING  FLAME 


ELEMENT 

COLOR  HOT 

COLOR  COLD 

Aluminum 

Colorless  to  Cloudy 

Colorless  to  Cloudy 

Antimony 

Yellowish 

Colorless 

Barium 

Colorless  to  Opaque 

Colorless  to  Opaque 

Bismuth 

Yellow 

Colorless 

Cadmium 

Yellow 

Colorless  to  White 

Calcium 

Colorless 

Colorless 

Chromium 

Reddish  Yellow 

Yellowish  Green 

Cobalt 

Blue 

Blue 

Copper 

Green 

Greenish  Blue 

Iron 

Orange 

Yellow 

Lead 

Yellow 

Colorless 

Magnesium 

Colorless 

Colorless 

Manganese 

Violet 

Reddish  Violet 

Nickel 

Violet 

Reddish  Brown 

Silver 

Colorless 

Milk-White 

Strontium 

Colorless  to  Opaque 

Colorless  to  Opaque 

Tin 

Colorless 

Colorless 

Zinc 

Yellowish 

Colorless 

PRINCIPAL  ORES  BEFORE  THE  BLOWPIPE     ?$ 


IV 


TABLE  OF  COLORS  OF  BORAX  BEADS  IN  REDUCING  FLAME 


ELEMENT 

COLOR  HOT 

COLOR  COLD 

Aluminum 

Colorless 

Colorless 

Antimony 

Colorless 

Cloudy 

Barium 

Colorless 

Colorless 

Bismuth 

Colorless 

Gray  —  Cloudy 

Cadmium 

Colorless 

Gray  —  Cloudy 

Calcium 

Colorless 

Colorless 

Chromium 

Green 

Green 

Cobalt 

Blue 

Blue 

Copper 

Colorless 

Red 

Iron 

Yellowish  Green 

Yellowish  Green 

Lead 

Colorless 

Gray 

Magnesium 

Colorless 

Colorless 

Manganese 

Colorless 

Pink 

Nickel 

Colorless 

Gray  —  Cloudy 

Silver 

Colorless 

Gray 

Strontium 

Colorless 

Colorless 

Tin 

Colorless 

Colorless 

Zinc 

Colorless 

Gray 

BLOWPIPE  ANALYSIS 


TABLE  OF  COLORS  OF  MICROCOSMIC  SALT  BEADS  IN 
OXIDIZING  FLAME 


ELEMENT 

COLOR  HOT 

COLOR  COLD 

Aluminum 

Colorless 

Colorless 

Antimony 

Yellowish 

Colorless 

Barium 

Colorless  to  Opaque 

Colorless  to  Opaque 

Bismuth 

Yellow 

Colorless 

Cadmium 

Yellowish 

Colorless 

Calcium 

Colorless 

Colorless  to  Opaque 

Chromium 

Reddish 

Green 

Cobalt 

Blue 

Blue 

Copper 

Green 

Greenish  Blue 

Iron 

Red 

Brownish  Red 

Lead 

Yellowish 

Colorless 

Magnesium 

Colorless 

Colorless 

Manganese 

Brownish  Violet 

Reddish  Violet 

Nickel 

Reddish 

Yellow 

Silver 

Yellowish 

Yellowish 

Strontium 

Colorless 

Colorless 

Tin 

Colorless 

Colorless 

Zinc 

Yellowish 

Colorless 

PRINCIPAL   ORES  BEFORE  THE  BLOWPIPE    77 


VI 

TABLE  OF  COLORS  OF  MICROCOSMIC  SALT  BEADS  IN 
REDUCING  FLAME 


ELEMENT 

COLOR  HOT 

COLOR  COLD 

Aluminum 

Colorless 

Colorless 

Antimony 

Colorless 

Gray  —  Cloudy 

Barium 

Colorless 

Colorless 

Bismuth 

Colorless 

Gray  —  Cloudy 

Cadmium 

Colorless 

Gray  —  Cloudy 

Calcium 

Colorless 

Colorless 

Chromium 

Reddish 

Green 

Cobalt 

Blue 

Blue 

Copper 

Dark  Green 

Brownish  Red 

Iron 

Red 

Reddish 

Lead 

Colorless 

Gray  —  Opaque 

Magnesium 

Colorless 

Colorless 

Manganese 

Colorless 

Colorless 

Nickel 

Colorless 

Gray 

Silver 

Colorless 

Gray 

Strontium 

Colorless 

Colorless 

Tin 

Colorless 

Colorless 

Zinc 

Colorless 

Gray  —  Cloudy 

THE  PRACTICAL  METHODS 

OF 

ORGANIC  CHEMISTRY 

AUTHORIZED  TRANSLATION 
1 2 mo.    Cloth.    Price,  $1.60,  net 

BY  TRANSLATED  BY 

LUDWIG  GATTERMANN,  Ph.D.,         WILLIAM  SHAFER,   Ph.D., 

Professor  in  University  of  Heidelberg.         Instructor  in   Organic    Chemistry 

in  Lehigh  University. 


THE  GUARDIAN. 

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is  a  most  useful,  practical  adjunct  to  any  good  text-book  on  organic 
chemistry." 

PHARrtACEUTICAL  REVIEW. 

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organic  chemistry,  and  one  which  will  no  doubt  be  of  great  value 
to  students  in  their  second  year  of  organic  chemistry.  Its  chief  pecu- 
liarity and  merit  is  in  the  great  stress  laid  on  practical  laboratory  work. 
...  It  is  permanently  a  worker's  guide." 

NATURE. 

"  Since  the  advance  of  organic  chemistry  in  this  country  must,  in  a 
measure,  depend  on  the  nature  of  the  available  text-books,  both  the 
author  and  the  translator  deserve  our  thanks  for  providing  us  with 
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PUBLISHED   BY 

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OUTLINES 

OF 

INDUSTRIAL  CHEMISTRY 

A  TEXT-BOOK  FOR  STUDENTS 
By  FRANK    HALL  THORP,   Ph.D., 

Instructor  in  Industrial   Chemistry  in   the  Massachusetts  Institute 
of  Technology. 

Cloth.    8vo.    Price,  $3.50  net 


JAMES  LEWIS  HOWE, 

Department  of  Chemistry,  Washington  and  Lee  University. 

"  The  book  is  brought  thoroughly  up  to  date,  and  in  some  cases  the 
lines  of  probable  development  are  nicely  foreshadowed.  The  descrip- 
tions are  particularly  lucid  and  the  illustrations  well  selected. 

The  general  arrangement  and  make-up  of  the  book  is  excellent,  and 
. .  .  altogether  the  book  fills  well  a  need  long  felt  by  teachers  of  Indus- 
trial Chemistry. 

I  shall  adopt  the  book  for  my  class  and  shall  take  pleasure  in 
recommending  it." 

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Professor  of  Chemistry,  Louisiana  State  University. 

"  I  have  examined  it  carefully  and  think  it  a  most  excellent  book, 
meeting  a  want  I  have  long  felt  in  my  higher  classes.  I  have  intro- 
duced it  in  this  year's  classes." 

W.   A.   NOYES,  in  Science. 

"  The  descriptions  of  processes,  while  necessarily  concise,  are  clear 
and  interesting.  The  author  has  evidently  made  a  careful  study  of 
recent  methods  of  manufacture  as  well  as  of  older,  standard  processes. 
The  frequent  reference  to  American  practice  is  an  important  feature 
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A  select  bibliography  follows  each  subject,  and  will  be  found  very 
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